Francis kelsey



UNITED sTATEs PATENT oEEIoE.

FRANCIS KELSEY, OF NEW YORK, N. Y.-

MILLSTONE.

Specification of Letters Patent No. 5,738, dated August 29, 1848.

To all-whom t may concern Be it knownrthat I, FRANCIS KELSEY, of thecity, county, and State of New York,

have invented a new and useful Improve-- ment in Millstones; and I dohereby declare that the following is a full and exact description of theconstruction and of the mode of constructing the same, reference beinghad to the annexed drawings, 4making part of this specification, inwhich- Figure l is a perspective view of the'mold in which the millstoneis formed, Fig. 2 represents the millstone as it appears when 1inishedand inverted: Fig. 3 represents the mold and the hoop partly filled withthe composition; and in Figs. 4 and 5 are shown the two kinds ofpartition boards'used in the process as hereinafter described. l

A circular face plate A A A is made of wood or metal, with the faceslightlyvelevated in the center; and on the center of the face plate isplaced a block B of the form of a frustum of a cone.

Eight or mo-re strips of wood or metal C C C, are nailed or otherwiseattached to the face of the plate and extend from the block to theperiphery. These strips are about one fourth of an inch thick at thecenterward end, and one eighth or less at the outward end; othersimilar' st-ripsD D are placed intermediately between the first, inwhatever position furrows are required in the face of the millstone: theuse of all these strips, is to form furrows or grooves in the face oft-he stone, and to serve as guides in the arrangement of the stonefacings. A hoop of iron plate E is placed upon the face plates, insideof the rim thereof, and the surface of the plate between the strips isnearly covered with at pieces of flint or other similar hard stone, withthe best faces s down. Those pieces are generally placed edgewise witht-he smoothest edge to the plate, and arranged according to the radiusthereof. Several partition boards F and G or strips of wood six incheswide and in form corresponding to those of the groove strips (asrepresented in Figs. 4L 'and' 5,) are p placed upon the groove stripsand extend from the center block B, to the hoop. These are slightlyattached to the groove strips vby small dowel pins, to keep them inplace, and a quantity of dilute cement made of almixture of waterlimeand water, or the ingredients of the common hydraulic `or Roman cement,is poured over the arranged fragments of flint, so as to fill allinterstices: and this cement is filled with other fragvments of stoneclosely packed. The hoop is then filled with the cement andstonefragments nearly to the top of the partition boards; and a quantityo'f the dry water lime is sifted over the composition to abn 'Sorb thewater that may rise above the surface while the cement is becomingconsolidated. When thiscomposition has become hard, the partition boardsare carefully extracted in the manner shown at I-I, Fig. 3, and theapertures or vacancies thus produced are filled with the liquid cement,or plaster of Paris mixed with water to a convenient consistence;y andthe hoop is also filled up with cement, and fragments of granite, orother stone, and dry water-lime is sifted over the whole to absorb thewater that'may rise to the surface. .When this composition has becomesuiiiciently hard, it

is inverted, the face piece and center block removed, and the millsto-neis left to dry, which ordinarily requires three `or four weeks.

What I claim as my invention and desire to secure by Letters Patent is-The mode of constructing 'millstones by means of the face plate, groovestrips, and partition boards, and the mode of arranging and securing thegrinding fragments, substantially as herein set forth.

' FRANCIS KELSEY. Witnesses: yRUEUS PORTER,

p JAMES DoNAHoE.

